Discuss the behaviour of p-n junction. How does a potential barrier develop at the junction ?

Explanation

When p-n junction is formed, the free electron on n-side diffuse over to p-side , they combine with holes and become neutral.Similarly holeson p-side diffuse over to n-side and combine with electrons become neutral.
This results in a narrow region formed on either side of the junction.This region is called depletion laer.Depletion layer is free from charge carriers.
The n-type material near the junction becomes positively charged due to immobile donor ions and p-type material becomes negatively charged due to immobile acceptor ions. This creats an electric field near the junction directed from n-region to p-region and causesa potential barrier.
The potential barrier stops further diffusion of holes and electrons across the junction. The value of the potential barrier depends upon the nature of the crystal, its temperature and the amount of dopoing.